Allyl Alcohol Is the Sole Antiyeast Compound in Heated Garlic Extract

The principal antiyeast compound of heated garlic was isolated and identified by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) as allyl alcohol (2-propene-1-ol). The generation of allyl alcohol was observed in heated garlic as well as in heated pure alliin solution. The pattern of growth inhibition of Candida utilis ATCC42416 by allyl alcohol was essentially the same as that seen with heated garlic and heated alliin solution. The minimum inhibitory concentrations of heated garlic, with an alliin content of 1.5% (w/v), and allyl alcohol were 0.6% (v/v) and 0.002% (v/v), respectively, against C. utilis ATCC42416. Yeasts were extremely sensitive to allyl alcohol, with minimum inhibitory concentration (MIC) ranging from 0.002% (v/v) to 0.014% (v/v), while bacteria were not very sensitive to allyl alcohol, with MIC ranging from 4% to 7%. Among yeasts, xerotolerant strains, including Zygosaccharomyces rouxii, were significantly less sensitive to allyl alcohol and heated garlic extract than others. Allyl alcohol is different from all other known antimicrobial compounds found in garlic in that it does not contain sulfur in its molecule.